A dramatic increase in the photostability of a blue-light-emitting polymer, poly(9,9-dioctylfluorene), was achieved by the addition of 5-10 nm gold nanoparticles. The optical absorption band of the gold nanoparticles was tuned to resonate the triplet exciton ground state bandgap energy of the polymer. Photo-oxidation rate of poly(9,9-dioctylfluorene) was effectively reduced by doping the polymer with very small amounts (approximate to10(-6)-10(-5) volume fraction) of the gold nanoparticles.